For many winemakers calculating the amount of sugar that is needed to obtain a certain percentage of alcohol is still a difficult subject.

A subject that keeps coming up on winemaking forums and even people send me mails about. Even a few days ago this subject came up on the Dutch winemakers forum Bibere. I will spare you the link as all is in Dutch. I was however flattered by the fact that the forum members used my SG table to do their calculations.

In all my recipes on this web-log I explain how to calculate the needed sugar addition. However, I do this by a calculation method that is for many people each time a pain to follow. Therefore in this story I am going to explain the normal way to calculate sugar that can simplify things a bit.

Off course I will demonstrate the method by a real-world example as I always do.

The 'normal method'

When making a wine you will firstly decide how much alcohol the wine will get. Therfore we always start with measuring how much sugar is already present in the juice we are turning into wine. Together these two are the base for calculating how much sugar we need to add to our must.

Imagine we make 10 liter white wine and we want this wine to have 11% alcohol. And when we measure the must with our hydrometer or refractometer it shows an SG of 1060.

My own SG-Table (which can be downloaded by clicking here) shows that there is 136 gram sugar per liter present in your must when the SG is at 1060.

Now we know that to get 1% alcohol in 1 liter we need 18 gram sugar to be present. So for our 10 liter wine we will need 10 liter x 11% x 18 gram = 1980 gram sugar.

We also know (by the measurement) that our must already contains 136 gram sugar per liter. For our 10 liter must that means that there is 10 liter x 136 gram = 1360 gram sugar already present.

We have 10 liter wine with an SG of 1060. So my tabel tells you that there is 136 gram sugar present per liter.

We want to get a wine with 11% alcohol.

Now look again at my table but now in the column alcohol. Well you will not find 11%. So look at the figure that comes closest to what we want. In this case that is 11.2% alcohol.

The table indicates that for getting 11.2% alcohol you will need to have 201 gram sugar per liter dissolved in the must.

Now the only thing we need to do is to subtract these to figures to know how much sugar we need to add per liter must.

So according to the table we need to have 201 gram sugar per liter. Again according to the table there is already 136 gram present. So we need to add 201 - 136 = 65 gram sugar per liter.As we are making 10 liter wine we only have to multiply the amount per liter by the number of liters we are going to make.In this case we are making 10 liter so we need to add 10 x 65 = 650 gram sugar.

So this method gives nearly the same result as our calculations do.

Where does the difference originates from

Well the difference is in the fact that when calculating the amount sugar needed we use the exact alcohol percentage we want to achieve. When you work with the table you do not get the exact amount of alcohol but a figure nearby.

in this particular example we want 11% alcohol but the table just gives an indication at 11.2% alcohol which is slightly higher. That is why by using this method you will add slightly more sugar and therefore the wine will get a slightly higher alcohol percentage.

The difference however is so small that there is nothing to worry about.

How does this turn out in real life.

Well I was just making wine from a storebought juice being: pomme-granate/ raspberry.

I decided to use and test this method for making this wine.

First let us look at the packaging. It indicates that there is just 2.8 gram sugar per 100 ml juice present. This sums up to 28 gram sugar per liter.

Now my hydrometer and refractometer both indicated an SG of 1018.

Lets see what my table makes of that.

As you can see my table does not know the value 1018 but it does indicates the value 1020. At an SG of 1020 according to my table there will be 32 gram sugar per liter dissolved in the must.We have a value that is a bit less.

So there should be a bit less as 32 gram sugar per liter present. And that is indeed what the packaging of the juice indicates: 28 gram.Again a proof that my table os fairly accurate.

I wanted to make a wine with about 11% alcohol.

You will not find 11% in my table as an indicated alcohol percentage. So we will look at the nearest available value being 11.2%.

My table indicates that to get 11,2% alcohol in a wine you will need to have 201 gram sugar per liter.

I was making 5 liter wine with this juice.So I needed 5 x 201 gram sugar. That totals 1005 gram sugar.

As indicated on the packaging and by measurement the juice contains 28 gram sugar per liter. In the 5 liter juice therefo0er there will be 5 x 28 = 140 gram sugar.

So you need to have 1005 gram sugar dissolved IN the total must. So when you just blindly add 1005 gram sugar TO the 5 liter must the total volume of your must will be more as 5 liter. Therefore the SG calculation is not accurate in that case.

When adding sugar TO a must the volume of the must will rise. That can confuse things. I once wrote a story on this subject which you can re-read by clicking here.

So if I would add 865 gram sugar TO my 5 liter juice the total volume would be a lot more as 5 liter.

So this is what I did.

I started by weighing 865 gram sugar and put it in a large pan. I added 1,5 liter juice to the sugar and while stirring I slowly heated the mixture which helped dissolving the sugar. Then I let it cool down again.

Next I poured the mixture in a large primary and added another 3 liter of the pomme-granate / raspberry juice. Again I stirred well.

The primary now contained 4,5 liter juice and 865 gram sugar dissolved in it. That is together about 5 liter with the right SG, assuming my theory was correct.

So I poured a drop of the must on the glass of my refractometer.

And presto !! The SG was at 1085 just where I wanted it to be.

The Sugar calculations in easy steps.

I will explain the procedure here again in easy steps.

- Measure how much the volume of your must is- Measure the SG of the must- Look-up the Sg in the table and decide how much sugar there is present in the must. This figure is marked A- Now decide how much alcohol you want to get in your wine- Loopup the amount of alcohol in the table and determine how much sugar there should be present to obtain that amount. Call this figure B- Now subtract A from B- Now you know how much sugar you need to add per liter must- Muliply this amount by the amount of liters you have

A few sidenotes

I will not force you to use my table. Use your own favorite table or any table found on the internet or in books. However my table is the best........ You can download it by clicking here.

Do NOT mix tables. Using my table for determining the SG of a juicde and then using Berry's table to calculate the amount of sugar to add to the juice is a bad idea. This will give you a totally false outcome. Stick to one table, again preferably mine.